Comparison Some Microbiological and Physicochemical Properties of Freeze Dryed and Spray Dryed Milk Powder

In this research, some microbiological and physicochemical properties of milk powder produced by freeze dryer and spray dryer were determined during the storage period. Firstly, milks were divided into two groups. First group was dryed with freeze dryer. Second group was dryed with spray dryer. Total aerobic mesophilic bacteria, mould-yeast, total coliform and fecal coliform, moisture, hunter colour determination, water activity, pH analyses were performed in 2., 4. and 6. days of storage at room temperatures. Water absorption index, water solubility index, protein and microscopy analysis was performed in 2.day, 6.day and 6.day of storage, respectively. Moisture, water activity, microbiological analysis, L value and water absorption index values of freeze dryed milk powders were found lower than spray dryed samples in all days of storage. Microbiological quality of freeze dryed milk powder is better. It was thaught that the milk powder produced by freeze drying may have a longer shelf life at room temperature